Actually, the Borg do *not* assimilate anything in their path. They only take those that would add to their perfection, the Kazon for example were not deemed 'worthy'.
I'd image a 1st contact between Borg and Pakled like this...
*Cube drops outta warp, scans Pakled vessel*
*Pakleds desperately run around on their bridge and can't decide which buttons to press*
*Borg Collective concertedly ponders.... "naaa..."*
*Cube goes back to warp*
*Pakled made up their minds, press buttons*
*Pakled ship ejects warp core*
*Pakled ship decompresses through opened shuttle bay door*